Electrical phase reversal device



April 9, 1940.

w.`H. Buss ELECTRICAL PHASE REVERSAL DEVICE- Filed Nov. 29, 19:58 l

ATTORNEY AuNrrupl STATES Patented Apr. e, 1940 Ilal'raN'r ori-Ica amasar llslLEiZilElCAL PHASE BEVERSAL DEVICE Warren H. Bliss, Orono, Maine, assignor to Radio l Application `passage through an electron tube.

A further object is to produce a reversal of alternating current or potential by reversal or gtlger variation of a D. C. bias of an electron Other objects will appear in the following de scription, reference being had to the drawing, in which; 1

Fig. 1 is a circuitv diagram showing one embodiment of my invention.

Fig. J2 illustrates lthe D. C. biasoutput voltage characteristic of the push pull circuit of iig. l and also the counter voltage of the by-pass circuit as well as the net voltage of the output.

Fig. 3 illustrates a particular phase adjusting device.

Fig. 4 illustrates a modification.

There are various uses for phase reversal circuits or devices, one such use being in telegraphy where the code characters in the communication of intelligence are produced by reversing the phase of an alternating current or potential, but my invention is useful in connection with any system where phase reversal is'described.

In Fig. 1, l illustratesa generator oi alternating current of any frequency. vThe generator is con nected by transformer 2 to the. input of a push pull vacuum tube stage The output of this push pull stage is fed through transformer@ to an output circuit 5, one terminal of which is grounded as is also one terminal of the alternating current source i, though obviously neither oi these is essential. The battery 6 alone is caiipagle of biasing the grids to the point i iny Fg. A resistance e is connected across the terminals oi' the alternating source i. An adjustable tap 9 is connected to this resistance and to a ter mnal of transformer d and also to an adjustable resistance l@ grounded at il. In this connection either a condenserl I2 or an inductance it may be inserted bythe switch. arrangement ift.- iE, to control the phase of the current.

The positive terminal i@ oi the plate supply of the push pull stage is connectedto the center of the primary ci' transformer and also to a tap i1 adjustably connected to resistance iii Y Corporation of America, a corporation of Dela- November 29,1938, Serial No. 242,884

-. im. (CL 178-66) though the resistance andv tap may be omitted when desired.l 'Ine-negative terminal I9 of 'the plate supply is connected to ground, as shown.

The common return'oi the grids of the vacuum tubesinclude a variable part of resistancew as a variable control bias. The value ofthe con-B trol bias 1s adjusted hy means of the tap 2i connected to thefbiasing battery t.

While a variable control blasof proper value and of any frequency of variation, may be made to'produce the reversal of phase ofthe alten' conductor 23 with contact 24 of the telegraph lrey and the other conductor 25 is connected tothe contact 26 of the telegraph key.- With this arrangement the spring 2l holds the key in position lto apply by means oi' battery 29 a positive bias in series with the negative bias S. There is then minimum negative, or most positive bias on the grids oi the tubes. When the key' is de pressed a negative D. G. potential is applied in series with the negative bias d. in this position the two bias voltages add and produce maximum negative D. C. bias on the grids.

As will be noted from the circuit arrangement ci Fig. 1, part of the output of the generator i proceeds directly through the push pull stage to the output 5 and another part passes through the tap t, conductor, condenser i2 or inductance IS, as the case may be. to resistance id and baal; to the alternating source through ground. l voltage drop'is thus produced in resistance' id. This drop is in series with the voltage produced in the secondary ci the transformer d.' By proper adjustment of the condenser l2, or of inductance it, as the case may be, the voltage 'drop in the resistance I0 may be readily made to be 18W out of phase-With the voltage produced in the secondary oi transformer 4, and by adjustment of either the tap Q or the resistance it, or both of them, the value'oi the drop in resistance id may be readily made equal to the voltage at the terminals of the secondary oi' the transformer d.

With the reslstances 9 and `2li all out oi the ley-pass and grid circuits, respectively, and negative bias value 1 the amplified A. C. voltage has the value 3i of's'cale I of Fig. 2. Ii now the proper adjustments are made for value and phase, the bi1-passed voltage appearing in resistance l0 is equal toand opposite to theampliiled voltage. The output voltage-is then zero.

With the tap 2l suitably adjusted on the resistance 20 and with the key in the upper position, a positive bias from battery 2l is applied to the grids of the push pull tubes in opposition to the normal negative bias of battery 6. This decreases the negative bias or renders it positive, depending upon the tube characteristics and carries it to point in Fig. 2. The value of the amplified voltage is given by 32 on scale I, while the by-passed voltage still has the value 8l. Scale 1I gives at 33 the resultant or output voltage with the zero value of Ithe' scale on the line through point 3|. This voltage of course has the phase of the amplified voltage.

With the telegraph key 22 depressed the potential of the battery 29 is applied in the reverse direction. As before, the by-passed voltage ap=ll pearing in resistance I0, will be unchanged in both value and phase but the amplified voltage will now be less because the amplification is de-a creased with increase of negative bias to point 3d. With this bias it has the value given by 35. The net voltage has the value given by 36 of scale 1I. Since the unchanged by-passed voltage pre dominates, the output voltage is 180 out of phase with the voltage given by 33, but equal thereto in value. The variation of the D. C. bias thus reverses the phase of the alternations but does not change the value, though obviously the value could be changed if this were desired.

The operation of the telegraph key 22 instantly reverses the phase of the alternating potential and the reversal of phase has no appreciable lag, being as fast as the flow of electrons. Of course there is a lag in the mechanical operation of the key 22 for reversing the D. C. potential but this telegraph key'ls merely an example selected for explaining the operation. It will be apparent that if the bias were varied at radio frequency there still would be nc appreciable lag in the reversal' of the phase of the alternating voltage.

My invention can be used regardless of the frequency of the alternating source, the phase of which is to be reversed. This generator may operate at very low frequency or at extreme ultra high frequency with no' difference in operation.

On low frequency or even at moderately high frequency laminated iron cores may be used in the transformers and inductances as shown in Fig. 4. At high or very high frequencies the condenser I2 may have rotor plates interleaving with stator plates for producing the necessary adjustment of4 capacity. At lower frequencies a condenser of proper value would be selected and placed in circuit or there may be a bank of condensers, as shown in Fig. 3. The inductance in any case would be more suitably adjusted by shortcircuiting some of the turns, as indicated in this Fig. 3, although vvariometers are obviously suitable, particularly at high frequencies.

The bias does not have to be of anydefinite value. After having balanced the by-passed voltage with the amplified voltage in phase and value the normal bias could be set at the point 8l. The phase of the alternations could then be reversed by applying a D. C. negative voltage that would carry the bias down to point 34.

Obviously the normal bias source 6 could be omitted and the phase reversal secured by balancing the voltages at the point on the curve where there is zero bias and varying or reversing the bias from the source 29 about this point.

'This invention obviously is not limited to a push pull arrangement of the tubes as a.' single tube can be used with like results.

It will be apparent that thecounter E. M. F.

`a source of alternating potential connected to could be impressed on the output of the ampliner in a variety of ways; an additional way being indicated in Fig. d where parts similar to those of Fig. 1 have been given similar reference characters. 5

Various other modifications in this and other features may be made without departing from the spirit of the invention.

Having described my invention, what I claim is:

l. In an electrical phase reverser, an amplifier l0 tube having a control electrode, a cathode and an anode, input and output circuits for said tube,

a source of alternating potential connected to said input circuit, means for producing in said output circuit a voltage equal and opposite to 15 the voltage ,produced therein by said amplifier tbe, and means for increasing and reducing the last mentioned voltage equal amounts above and below the next to last mentioned voltage for reversing the phase of the resultant alternating 20 voltage in said output circuit.

2. In an electrical phase reverser, an amplifying tube having a control electrode, a cathode and an anode, input and output circuits for said tube,

a source of alternating potential connected to 25 said input circuit, means including a by-pass for an anode, input and output circuits for said tube,

a source of alternating potential connected to said input, a by-pass connection between said 40 'source and said output, means for adjusting the value of the voltage impressed on said output through said by-pass to equal that of the output of said amplifier tube, and means to adjust the phase of the by-passed voltage 180 from the voltage in said output impressed through said tube, means for applying a variable bias' between the cathode and control electrode to alternately increase and decrease the amplified voltage aboveand below the by-passed voltage for reversing the phase of the resultant alternating voltage in said output circuit.

e. In an electrical phase reverser, an ampliiier tube having a control electrode, a cathode and an anode, input and output circuits for said tube, a source of alternating potential connected to said input circuit, a by-pass connection between said source and said output circuit, means for adjusting the value of the voltage impressed on said output circuit through said by-pass and means to adjust the phase of said voltage 180 from'the voltage in said output circuit impressed through said tube, means for biasing the' control electrodein respect to the cathode, and means for varying said bias forreversing the phase vof the resultant voltage in said output circuit.

5. In an electrical phase reverser, an amplifier tube having a control electrode, a cathode and an anode, input and output circuits for said tube,

said input circuit, a-bypass connection between said source and said output circuit, means for adjusting the value of the voltage impressed on said output circuit through said by-pass and means to adjust the phase of said voltage -75 from the voltage in said output circuit impressed through said tube, a source of unidirectional voltage for biasing the control electrode in respect to the cathode and means for applying a variable bias between the cathode and control electrode to alternately increase and decrease the amplified voltage above and below theby-passed voltage for reversing the phase of the resultant alternatv ing voltage. in said output circuit. 6. In an electrical phase reverser, 'an ampliiler ltube having acontrol electrode, a cathode and `an anode, input and output circuits for said tube, a source of alternating potential connected to said input circuit, a by-pass connection between said source and said output circuit, means for adjusting said. connection to impress on said output circuit through said by-pass a voltage equal in vvalue to and opposite in phase from the voltage in said output circuit impressed through said tube, a. source of 'unidirectional voltage for biasing the control electrode in respect to the cathode and means for varying said additional source to alternately increase and decrease the ampliiied voltage above and below the by-passed` voltage for. reversing the phase of the resultant alternating voltage in said output circuit.

'7. In an electrical phase shifter two amplier tubes connected in push pull relation, said tubes having control electrodes, anodes and cathodes, a source of alternating potential connected between the control electrodes of said tubes, a negative bias connected between the control electrodes and the cathodes, an output circuit connected to said anodes, a by-pass betweenthe source of alternating potential andthe output circuit of said tubes for producing an alternating voltage in sa'id output circuit equal and opposite to the voltage impressed on said output circuit through said tubes, and means-for applying a variable bias between the cathode and control electrode to reverse the phase of the net voltage in said output circuit. .A

8. In any electrical phase shifter, two amplifier tubes connected in push pull relation, said tubes i having control electrodes. anodes and cathodes, an input circuit connected tosaidl control'electrodes, a source of alternating potentials vconnected to said input circuit, a negative bias connected between the control electrodes and the vcathodes, an output circuit connected .to said anodes, a by-pass from said source around .the ampliner tubes for producing an alternating voltage in said output circuit,equal and opposite to the voltage impressed on 'said output circuit through said tubes. means for biasing the control electrodes in respect to the cathodes and means for varying said -biasto cause each of said voltages to predominate alternately over the other for reversingl the phase oi' the resultant alternating voltage in said output circuit.

9. In anelectrical phase reverserran tube having a control electrode, a cathode and ananode.inputa'ndoutputcircuitsiorsaidtube, ascurceof altematinglll. ltoonnectedto ampliner said input circuit for producing an alternating E. M. F. in the output circuit, means for producing in said output circuit an alternating E. M. F. of opposite phase' to that produced thereinby said amplifier tube, and means for increasing one ofthe output E. M. F.s above the other for producing va. resultant alternating E. M. F. of one phase and for reducing it below the other for producing an alternating' E. M. F. of opposite phase.

10. In an electrical phase reverser, an amplifying tube having a'control electrode. a cathode and an anode, input and output circuits for said tube, a. source of alternating E. M. F. connected to said input circuit for producing an alternating E. M. F'. irlsaid output circuit, means for producing in said output circuit an alternating E.y M. F. of opposite phase to that produced therein by said amplier tube, and means for applying a variable bias between-the cathode and control electrode for increasing the amplified E. M` F. above the by-passed E. M. F. for producingin the output circuit a resultant E. M. F. of one phase and lor decreasing it therebelow for producing an alternating E. M. F. of opposite phase.Y

11. In an electrical phase shifter two amplier tubes connected in push-pull relation, said tubes having `control electrodes, anodes and cathodes, a source of alternating E. M. F. connected to the input lcircuit of said tubes and producing an alternating E. M. F. in the output circuit, a negative bias connected between the control electrodes andthe'cathodes, a by-pass between the source i of alternating E, M. F. and the output circuit of said tubes having means for producing an alterhating E. M. F. in said output circuit opposite in phase to the E. M. F. impressed on said output circuit through said tubes, and 'means for varying said bias for increasing the amplified E. M. F.

, pass from said source around the amplifier tubes having means for producing an alternating E. M. F. in said output circuit, opposite to the E. M. F.- impressed on said output circuit through said tubes with a bias of said value, means .for

increasing the value of said bias to produce in4 the output circuit an alternating E. M. F. of one phase and for decreasing the said value to produce therein an alternating E. M. F. of opposite fWARRENEBLISB. 

